Veterinary World, Vol.3(4): 198-200 REVEIW Bone Grafting : An Overview

D. O. Joshi , P. H. Tank , H. K. Mahida, M. A. Dhami*, H. S. Vedpathak and A. S. Karle

Department of Veterinary Surgery & Radiology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand- 388 001, Gujarat, India. * Corresponding author

Abstract Bone grafting is the process by which bone is transferred from a source (donor) to site (recipient). Due to trauma from accidents by speedy vehicles, falling down from height or gunshot injury particularly in human being, acquired or developmental diseases like rickets, congenital defects like abnormal bone development, wearing out because of age and overuse; lead to bone loss and to replace the loss we need the bone grafting. Osteogenesis, osteoinduction, osteoconduction, mechanical supports are the four basic mechanisms of bone graft. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. An ideal bone graft material is biologically inert, source of osteogenic, act as a mechanical support, readily available, easily adaptable in terms of size, shape, length and replaced by the host bone. Except blood, bone is grafted with greater frequency. Bone graft indicated for variety of orthopedic abnormalities, comminuted fractures, delayed unions, non-unions, arthrodesis and osteomyelitis. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. By adopting different procedure of graft preservation its antigenicity can be minimized. The concept of bone banking for obtaining bone grafts and implants is very useful for clinical application. Absolute stability require for successful incorporation. Ideal bone graft must possess osteogenic, osteoinductive and osteocon-ductive properties. Cancellous bone graft is superior to cortical bone graft. Usually autologous cancellous bone graft are used as fresh grafts where as allografts are employed as an alloimplant. None of the available type of bone grafts possesses all these properties therefore, a single type of graft cannot be recomm-ended for all types of orthopedic abnormalities. Bone grafts and implants can be selected as per clinical problems, the equipments available and preference of the surgeon. A search for ideal bone graft is on and may continue till time to time. Keywords: Bone, Bone graft, Trauma.

Introduction (Heppenstall, 1980). As the history reported, religious The term bone grafting refers to the process by elders threatened the surgeon to retrieve the bone, which bone is transferred from a source (donor) to site when the surgeon attempted to do so; it was already (recipient) (Bojrab, 1997) and indicated in aggressive fused in place. Schroeder (1938) used bone grafts first tumor resection, refractory nonunion, mandibular and time in veterinary orthopedics. calvarial reconstruction, composite defect (bone, skin Principles of Bone Grafting and muscle), to replace comminuted fragments, to (1) Osteogenic activity or potentiality of the transplant lengthen bones to correct malunions, delayed unions, material. for early production of bone and osteomyelitis (Brinker (2) The ability of graft to survive and proliferate. et al., 1990). Bone graft used in general as a framework (3) The immune response of the host. to provide stability, treatment of pseudoarthrosis and to (4) The degree of induction that the new transplanted stabilize spinal segments and addition of bone stock in material will experience and total joint replacement (Friedlaender, 1987). The firs1t (5) Affinity, which the host tissue exhibit towards the recorded attempt to use bone graft was by the Dutch interstices of the implanted bone (McLean and Urist, surgeon Job Van Meek’ren in 1668. Church literatures 1968). mention first transplantation of a bone graft in a Classification Russian soldier with dog’s cranial bone in 1682 Knowledge of bone graft classification is www.veterinaryworld.org Veterinary World, Vol.3 No.4 April 2010 198 Bone Grafting : An Overview necessary to understand the indications, contra- autoclaving, deproteinizing, aqueous merthiolating, indications, functions and the biology of various types freeze-drying (-150C to -300C), ethylene oxide of bone grafts (Martinoz and Walker, 1999). Autografts sterilization and radiation (Slatter, 2003). Bones have are transplantation into the same individual; allografts been stored for up to 1 year with colder temperature. are in same species while xenografts into different Freeze dried grafts may be stored at room temperature species and isografts into same family. Alloimplants are under vacuum or be frozen (-7000C) up to 5 years. nonviable graft. Cancellous graft (30-90% porosity) has Frozen graft should be thawed in warm physiological the greater osteogenic ability. Cortical grafts (5-30% solutions just before use. Cell death results from all porosity) most commonly used to provide stability these techniques and the grafts functions mainly as (Binnington, 1990). Autogenous/aspirated bone space filler and as a scaffold. Careful donor screening marrow used to provide live undifferentiated and strict adherence to aseptic harvesting technique mesenchymal. Corticocancellous grafts are are not necessary when using ethylene oxide to combination of cortical and cancellous bone. sterilize bones grafts and graft can be stored up to 3 Osteochondral grafts consist of a bone and articular years. The lower the temperature the longer would cartilage. Small chips of bone are particulate graft remain useful (Tomford et al., 1983). The allografts are (Habal and Reddi, 1992). Fresh grafts are removed and labeled with the donor’s identification, the date and the used immediately. Free grafts are not vascularized and bone location. The graft is recultured and radiograph at depend upon the local environment and ingrowth of the time of placement (Slatter, 2003). new vessels to function. Vascularized grafts are Cognizance Taken segment of whole bone removed with blood vessels and placed with the anastomosis (Finkemeir, 2002). Cognizance must be taken in respect to the Onlay grafts are simple or massive slats of bone. Inlay magnitude and location of the defects, anatomical grafts are cortical part of bone used for direct inlay or function of the involved bone and joint, biomechanical sliding inlay in long bones. The recipient site is carefully stresses and the cosmetic implication’s surrounding prepared and held in place by wedge effect, cortical the defect repair with minimal amount of trauma, bone screw, cerclage steel bands and smillie nails. The biocompatibility and physiological stability (Bojrab, grafts with muscle insertion are muscle pedicle 1997). Trauma should be minimize, oscillating bone transplanted into a surgically created slot in the saws should not be used as they cause a marked posterior femoral neck in young patients (Habal and temperature rise leading to cell death. It is best to wrap Reddi, 1992). The fibula and the rib are commonly used the graft in the patient’s own blood soaked sponge for spine as strut grafts. Clothespin (H) grafts are full- (Slatter, 2003). thickness iliac crest bone strips slotted both primarily Basic Mechnisms and distally and then placed between spinal processes for fixation. Orthotopic grafts are placed anatomically at 1. Osteogenesis is formation of the new bone by the appropriate site. Heterotopic grafts are placed at osteoblasts and osteoclasts. Cancellous inappropriate site. Demineralized bone grafts are potentially forms new bone than the cortical graft prepared by leaching minerals from the bone without due to its “spongy” structure. destroying the collagenous and non-collagenous 2. Osteoinduction is a transfer of undifferentiated protein; prepared in block or powder form. Powder form mesenchyma into osteoblast (Urist,1976). increases the surface area, more convenient as cells 3. Osteoconduction is three-dimensional process easily penetrate powder and moulds nicely especially of ingrowth of capillaries, perivascular tissue and as it mixes with blood (Abbott et al., 1947). Synthetic mesenchymal cells. New viable bone replaces grafts avoid morbidity but are not vascularized, may be old necrotic bone by dynamic process known as infectious, toxic or carcinogenic (Galletti, 1988). creeping substitution. 4. Mechanical supports are weight bearing struts Bone Bank that fill in large bony defects therefore providing Bone bank concept was laid by American strength and structure (Slatter, 2003). association of tissue bank and it has been used in Complications veterinary orthopedics for many years (Bojrab, 1997). Bone grafts can be harvested from wing of ileum, Surgical complications seen are non-union, proximal humerus, proximal tibia, distal radius, rejection, fracture (as fixation loosens), premature Sternum and ribs (Johnson, 1991). Recipient site is fracture, infected sequestrum, infection, and easily defined with radiograph and graft will form osteomyelitis (Slatter, 2003). Immunological graft scaffold; adequate bridging and stabilization with rigid rejections can be prevented by proper processing. The internal/external fixation require (Burchadt and mechanism of autograft rejection seems to be related Enneking, 1978). Preserved grafts are removed before most strongly to cellular rather than humoral immunity use, prepared and stored. Techniques are boiling, (Burwell, 1963). www.veterinaryworld.org Veterinary World, Vol.3 No.4 April 2010 199 Bone Grafting : An Overview

Disadvantages 4. Brinker, W. O.; Piermattei, D. L. and Flo, G. L. (1990). Delayed union and non union. In Handbook of small Disadvantages are limited resources, immune Animal Orthopedics and fractures treatment (2nd Ed). mediated rejection, technical difficulties in W. B. Saunders. Philadelphia. pp: 71. vascularized grafts, increase anaesthetic time and post 5. Burchadt, H. and Enneking, W. F. (1978):Transplantation operative bleeding, surgical invasion, morbidity and of bone Surg. In Slatter, D. H. (3rd Ed). W. B. Saunders iatrogenicity. Dehydration jeopardizes the stability of Company. Philadelphia. pp: 2038-2044. repair. Preserved grafts do not immediately produce 6. Burwell, R. G. (1963). Studies in the transplantation of bone: The capacity of fresh and treated homograft of bone and risk of morbidity at the donor site (structural bone to evoke transplantation immunity. J. Bone Joint weakening, infection, hemorrhage, pain, nerve injury Surg. 45(B): 386. and persistent deformity) (Martinoz and Walker, 1999). 7. Finkemeir, C. G. (2002). Bone-grafting and bone graft Even the lowest dose of radiation can cause substitutes. J. Bone Joint Surg. Am. 84(A): 454-464. destruction of morphogenic property (BMP) of bone 8. Friedlaender, G. E. (1987). Current concept review. (Urist, 1976). Bone grafts: The basic science rationales for clinical applications. J. Bone Joint Surg. 69: 786-790. Future Prospects 9. Galletti, P. M. (1988). Artificial organs: Learning to live Future prospects underlying this area may with risk. Technology Review Nov/Dec: 35-40. 10. Habal, M. B. and Reddi, A. H. (1992). Bone grafts and include the use of biopreparations like bioceracol bone Substitutes. W. B. Saunders Company. (water-soluble bioceramics, microcrystalline, gelatine, Philadelphia. pp: 6-52. glycerol, sorbitol and nitrox). Collagenous and non 11. Heppenstall, R. B. (1980). Bone grafting. In Hepenstall collagenous protein within bone will be available to R. B. (Ed). Fracture treatment and healing. W. B. orthopaedic surgeons in the future. Stem cell therapy, Saunders Co. Philadelphia. pp: 97. development of injectable formulations, better delivery 12. Johnson, A. L. (1991). Principles of bone grafting. systems and gene therapy applications for growth Semin. Vet. Med. Surg. (Small Ani.) 6: 90-99. factors and osteoinductive substances. This article 13. Martinoz, S. A. and Walker, T. (1999). Bone grafts. Vet. Clin. North. Am. Small Anmal. Pract. 29: 1207- reviews what is currently available and what is on the 1219. horizon. In addition, as investigators continue to find 14. McLean, F. C. and Urist, M. R. (1968). Bone, (3rd Ed). new materials and biologic approaches to bone repair, Chicago University of Chicago Press. pp: 554. the future of bone graft substitutes continues to be an 15. Schroeder, E. F. (1938). Intramedullary pegging of expanding topic. femoral fractures with beef bone. J. Am. Med. Assoc. 93: 109. References 16. Slatter, D. H. (2003). Textook of small animal surgery 1. Abbott, L. C., et.al.(1947). The evaluation of cortical (3rd Ed). Saunders, W. B.; Philadelphia. pp: 1875-1891. and cancellous bone as grafting material: A clinical and 17. Tomford, W. W., et.al.(1983). Bone bank procedures. experimental study. J. Bone Joint Surg. 29(A): 381. Clin. Orhto. Rel. Res. 174: 15. 2. Binnington, A. (1990). Bone Remodelling and 18. Urist, M. R. (1976). Practical application of basic Transplantation. In Whittick Williams: Canine research on bone graft physiology. In American Orthopedics. Philadelphia. 67: 166-189. Academy of Orthopaedic Surgeons Instructional course 3. Bojrab, M. J. (1997). Bone grafting principles and Lectures, XXV, and St Louis: C. V. Mosby: 1 from Nixon, techniques. In Current technique in small animals A. J. Equine fracture repair. W. B. Saunders Company surgery (4th Ed). pp: 901-910. Philadelphia. pp: 87. ********

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